The TS<->Python communication channel uses stdout for JSON responses.
pcbnew's C++ SWIG layer can write warnings and diagnostics directly to
C-level stdout (fd 1), corrupting the JSON framing. The TS parser then
never sees valid JSON and the command times out after 30 seconds.
Three changes fix this:
1. Python stdout redirect: In main(), save the original stdout fd for
exclusive JSON response use, then redirect fd 1 to stderr so all
pcbnew C++ output goes to logs instead of the response pipe.
2. Robust TS JSON parser: tryParseResponse() now uses newline-delimited
parsing as a fallback. The Python side writes single-line JSON
terminated by \n; the parser uses this as the completion signal
instead of brace-matching, which prevents premature resolution of
truncated chunked responses. Non-JSON preamble lines are logged
and stripped.
3. Fix stray print() calls: Converted print() to logger in
component_schematic.py and library_schematic.py so they don't
leak to stdout during normal operations.
Also adds sync_schematic_to_board to the longRunningCommands list for
an appropriate timeout value.